1. Field of the Invention
The present invention relates to new crystalline forms and salts of 1-(3′,4′-dichloro-2-fluorobiphenyl-4-yl)cyclopropanecarboxylic acid of the following formula:
The present invention also relates to methods for the prevention and treatment of medical conditions such as Alzheimer's Disease and other forms of dementia by administering such a crystalline form or salt.
2. Discussion of the Background
Alzheimer's Disease is a devastating neurological disorder affecting more than 37 million people worldwide. As yet, there are no approved drugs capable of preventing or reversing the disease. A particular focus of research and development efforts is on preventing formation of synaptotoxic β-amyloid (Aβ) peptide in the brain and its aggregation into plaques.
The gamma secretase modulator compound 1-(3′,4′-dichloro-2-fluorobiphenyl-4-yl)cyclopropanecarboxylic acid was first described in patent application WO 2004/074232 as one of a large number of candidate therapeutic agents for neurodegenerative diseases such as Alzheimer's disease. That application does not disclose any crystal forms or specific salts of the compound.
Polymorphism is defined as the ability of a substance to crystallize in more than one crystal lattice arrangement. Polymorphism can influence many aspects of solid state properties of a drug. Different crystal modifications of a substance may differ considerably from one another in many respects, such as their solubility, dissolution rate and bioavailability.